An In-vitro Dissolution Profile and Impurity Analysis Comparing Commercially Available Dutasteride Tamsulosin Fixed Drug Combinations

Aims: This in vitro study aimed to assess Dutas T+ pharmacokinetics (dissolution) and impurity profile in comparison with other brands.

Study Design: In vitro dissolution study.

Place and Duration of Study: Theta-Beta Algorithms, India for the duration of one month.

Methodology: The dissolution of dutasteride was done by using type-2 apparatus (75 rpm) with the chromatographic system (240 nm detector). The percentage of the labelled amount of dutasteride dissolved was then calculated. The dissolution of tamsulosin hydrochloride involved acid stage (0.1 N hydrochloric acid) and buffer stage (0.1N hydrochloric acid and a sodium phosphate buffer) and was done by using type-2 apparatus (50 rpm) with the chromatographic system (225 nm detector). The tailing factor was NMT 2.0. Further, the impurities tested for dutasteride were Desmethyldutasteride, and Dihydrodutasteride and for tamsulosin were 2-methoxy, 5-benzenesulphonamide, and 2-propan-2-amine. Detection was done using spectrophotometer at 220 nm and 225 nm for dutasteride and tamsulosin respectively.

Results: In vitro dissolution profiles show that Dutas T+ achieves the highest release of dutasteride compared to other brands. No release of tamsulosin is observed in any formulation within the first 2 hours at the acid stage. However, after 7 hours in the buffer stage, Dutas T+, brand A, and brand B exhibit nearly complete dissolution. Dissolution times for dutasteride vary significantly among formulations, with Dutas T+ dissolving over 75% in 5 minutes, while brand A takes 30 minutes for complete dissolution. For tamsulosin hydrochloride, Dutas T+ reaches 50–75% dissolution in 3 hours and full dissolution in 4 hours, compared to brand C, which takes up to 6 hours, and brand B, which completes in 3 hours. All formulations show no detectable impurities for both dutasteride and tamsulosin. Dutas T+ shows statistically better dissolution, with 94% of the drug released in 7 hours, compared to Brand C (p<0.001), Brand A (p=0.061), and Brand B (p=0.150).

Conclusion: Dissolution studies indicate that Dutas T+ excels in releasing both dutasteride and tamsulosin compared to other formulations. All formulations showed no detectable impurities, confirming high purity levels.